Crankcase drainings recycling system

ABSTRACT

Disclosed herein is a fuel supply system for a two-stroke engine including a crankcase and a fuel feeding means, said system comprising a fuel tank communicating with the fuel feeding means and including a filler cap having means for sealing the interior of the fuel tank from the atmosphere, and means including a drainage tank communicating through one-way check valves with the fuel tank and the crankcase for conducting drainings from the crankcase to the fuel tank, for preventing escape of fuel vapor from the fuel tank when the engine is not operating, and for venting of excessive vapor pressure in the fuel tank to the fuel feeding means when the engine is operating.

[73] Assignee: Outboard Marine Brown [45] Jan. 9, 1973 CRANKCASEDRAININGS RECYCLING SYSTEM [75] Inventor: Peter W. Brown, Zion, Ill.-

Corporation, Waukegan, Ill.

22 Filed: 11111.21, 1971 [21] Appl.No.: 108,513

[52] US. Cl. ..l23/73 R, 123/136, l23/DIG. 2

[51] Int. Cl. ..F02b 33/04, F02m 37/00- [58] Field of Search ..l23/l36,73 R, 73 A, 73 B, 123/DIG. 2, 73 PP, 73 SC [56] I I 1 References CitedUNITED STATES PATENTS 3,093,124 6/1963 Wentworth.....

Schou ..123/l36 Primary ExaminerWendell E. Burns Attorney-Robert E.Clemency, John W Michael, Gerrit D. Foster, Bayard H. Michael, Paul R.Puerne'r, Joseph A. Geinignani, Andrew 0. Riteris, Robert K. Gerling andSpencer B. Michael 57 ABSTRACT v Disclosed herein is a fuel supplysystem for a twostroke engine including a crankcase and a fuel feedingmeans, said system comprising a fuel tank communicating with the fuelfeeding means and including a filler cap having means for sealing theinterior of the fuel tank from the atmosphere, and means including adrainage tank communicating throughone-way check valves with the fueltank and the crankcase for conducting drainings from the crankcase tothe fuel tank, for preventing escape of fuel vapor from the fuel tankwhen the engine is not operating, and for venting of excessive vaporpressure in the fuel tank to the fuel feeding means when the engine isoperating.

14 Claims, 1 Drawing Figure CRANKCASE DRAININGS RECYCLING SYSTEMBACKGROUND OF THE INVENTION Under normal operating conditions acrankcase scavenged two-cylinder engine collects liquid fuel in thelower portion of the'crankcase, which liquid fuel is often referred toas drain. Such drains are not readily vaporized for travel through thetransfer passages to the cylinder under normal operating conditions. Asa consequence, in the past, such drains have been drained from thecrankcase and were commonly wasted overboard by being dumped into theexhaust system.

Various arrangements have been suggested in the past for resupplyingsuch drains to the engine for combustion. Examples of such arrangementsare disclosed in the Upton U.S. Pat. No. 2,717,584, issued Sept. 13,1955, in the Goggi U.S. Pat. No. 3,138,748, issued Apr. 14, 1964, and inthe Heidner US. Pat. No. 3,132,635,

issued May 12, 1964. When such drains are pumped from the crankcase to aholding tank such drains are introduced to the tank under pressure andsuch accumulating pressure is desirably vented.

Another vent problem occurs when a storage tank with fuel is exposed tosunlight and is heated. Such SUMMARY OF THE INVENTION The inventionprovides a fuel supply system which vents fuel vapors from a fuelstorage tank to an engine fuel feeding system only when the engine isoperating and only if the vapor pressure in the fuel storage tank isrelatively high. In addition, the invention also serves to provide anintegrated system for conducting drains from a crankcase to a fuel tankfor resupplyto the engine for ultimate combustion.

More specifically in accordance with the invention, there is provided avent line which communicates between an otherwise sealed fuel tank andthe engine fuel feeding system and which includes a valve movable to anopen position to thereby permit venting only as a consequence of engineoperation. Still more specifically, valve movement to the open conditionrequires the presence of an excessive vapor pressure in the fuel tank,together with engine operation to generate a sufficient quantity ofdrains which accumulate because of the excessive vapor pressure andwhich cause the opening of the valve.

In the specifically disclosed construction, the valve is opened by afloat member which is supported on the surface of the accumulateddrains. When there is insufficient vapor pressure, the drains resultingfrom engine operation will be immediately drained into the fuel tank.

Should excessive vapor pressure develop in the fuel tank, as forinstance, by reason of exposure of the fuel tank to the sun, such vaporpressure will prohibit discharge of drains into the fuel tank until thepressure generated by the accumulation of drains is greater than thevapor pressure or until the accumulation of drains causes operation ofthe float to open the vent valve. In the absence of engine operation,there would be no material accumulation of drains and therefor nomovement of the vent valve to open position.

Also in accordance with the invention, .the fuel vapors, as well as anyvapor or pressure associated with the discharge drain from the crankcaseare supplied to the intake manifold of the engine for induction into andcombustion in the engine, thereby precluding pollution, as well asavoiding an explosion and/or fire hazard. Y l I In the specificallydisclosed construction and in accordance with the invention, the drainsare discharged from the crankcase into a drainage or holding tank eitherfor more or less immediate drainage to the fuel tank or for accumulationin the event of excessive vapor pressure in the fuel tank. Also inaccordance with the invention, the vent valve when opened, communicatesthe upper portion of the fuel tank with an upper portion of the drainagetank which, in turn, communicates through a vent line with the fuelfeeding means.

One of the principal objects of the invention is the provision of anarrangement for preventing the escape of fuel vapor from a storage tankin the absence of engine operation.

Another of the principal objects of the invention is the provision of anarrangement operable only in response to engine operation to provide forventing of the excess fuel vapor present in a fuel storage tank to anengine fuel feeding-system.

Another principal object of the invention is the provision of anarrangement for selectively preventing and affording the venting of afuel storage tank by means which are integrated in a system which alsoserves to conduct drains from a crankcase to a fuel tank for resupply tothe engine and for ultimate combustion.

Still another principal object of the invention is the provision of anarrangement for desirably discharging crankcase drain to a fuel tank forresupply to the engine and eventual combustion, thereby eliminating apossible source of pollution.

Another principal object of the invention is the provision of a fuelfeeding system which isrelatively easy to manufacture and economical toinstall and operate, which will provide a long and useful life, andwhich serves to avoid pollution of the environment and to avoid the riskof fire and/or explosion.

Other objects and advantages of the invention will become known byreference'to the following description and accompanying drawing.

DRAWING The FIGURE is a schematic view of an engine fuel system inaccordance with the invention.

GENERAL DESCRIPTION carburetor 23 with a float bowl 2'7 and an intakemanifold 29 connecting the carburetor 23 to the engine cylinder (notshown). The carburetor 23 conventionally includes a throttle valve 31which is substantially closed when the engine 13 is not operating.

Also shown schematically in the drawings is a fuel storage tank 37having upper and lower portions 39 and 41 respectively. Included in thefuel storage tank 37 is a filling cap 43 including means which, when thefilling cap 43 is tightly closed, seals the interior of the fuel tank 37from the atmosphere.

Connecting the lower part 41 of the fuel tank 37 and the carburetorfloat bowl 27 of the fuel feeding means 21 is a duct or fuel line 47which, under normal operating conditions, supplies fuel from the fueltank 37 to the fuel feeding means 21.

In accordance with the invention, there is provided means for conductingthe drainings from the crankcase 17 to the fuel tank 37 and forpreventing escape of fuel vapor from the fuel tank 37 when the engine 13is not operating and for venting of excessive vapor pressure in the fueltank 37 to the fuel feeding means 21 when the engine 13 is operating. Asthe vented fuel vapor is permitted to escape from'the fuel tank 37 tothe fuel feeding means 21 only when the engine 13 is operating, suchvapor is fedto the engine cylinder and is not permitted to escape to theatmosphere.

While various other arrangements could be used, in the disclosedconstruction, such means comprises a drainage or holding tank 51 whichis closed, except as otherwise disclosed herein, and which includesupper and lower portions 53 and 57 respectively, and a float or othermember 59'mounted on the tank 51 for movement relative to an elevated orraised position in response to accumulation of a predetermined quantityof drainings in the drainage tank 51.

Also in accordance with the invention, drains are discharged from thedrains collecting crankcase portion 19 to the upper portion 53 of thedrainage tank 51 by a conduit or duct 63 connected between the drainagetank upper portion 53 and the crankcase drains collecting portion 19.The duct 63 includes, preferably adjacentto the crankcase 17, a checkvalve 67 which affords flow from thecrankcase 17 under conditions orrelatively high crankcase pressure but which prevents flow to thecrankcase 17 under conditions of relatively low crankcase pressure.

Also in accordance with the invention, any gaseous pressure conditionwhich may exist in the drainage tank 51 in response to pumping of drainsfrom the crankcase 17 to the drainage tank 51- is relieved or vented bya duct or vent line 71 communicating between the .drainage tank 51 andthe fuel feeding system 21 and, in

particular, between the drainage tank upper portion 53 and the intakemanifold 29. Fuel vapors which may travel from the drainage tank 51 tothe intake manifold 29 when the engine 13 is not operating arerestrained from travel into the atmosphere because of the substantiallyclosed condition ofthe throttle valve 31 when the engine is notoperating.

.Under normal engine operating conditions, when there is an absence ofexcessive vapor pressure in the fuel tank 37, drainingswhich aredischarged into the drainage tank are, in accordance with the invention,discharged through a-duct or conduit 73 which extends occurrence ofexcessive vapor pressure in the fuel tank 3'7, the duct 73 includes, inaccordance with the invention, a oneway valve 77 which affords flow fromthe drainage tank 51 to the fuel tank 37 when the pressure at thedrainage tank side of the valve 77 is greater than the vapor pressure inthe fuel tank 37 and which prevents fuel vapor flow from the fuel tank37 to the drainage tank 51 whenever the vapor pressure in the fuel tank37 exceeds the pressure operative on the' drainage tank side of thevalve 77, i.e., in the drains or in the gas present in the drainage tank51. Under normal operating conditions, when there is an absence ofexcessive vapor pressure in the fuel tank 37, the drains flow by gravityfrom the drainage tank 51 to the fuel tank 37.

Also in accordance with the invention, there is provided means forventing to the fuel feeding means 21, when the engine is operating, offuel vapors causing excessive pressure in the fuel tank 37. While otherarrangements might be employed, in the disclosed construction, there isprovided a duct or line 79 which communicates between the fuel tankupper portion 39 and the drainage tank upper portion 53 and which in.-cludes a valve 81 operable by the float" 59 in the drainage tank 51.More specifically, the valve 81 is normally closed to seal the fuel tank37 against escape of fuel vapor except when the float 59 is in itsraised position. The float 59 is located in the raised positiononly inresponse to the simultaneous occurrence of continued operation of theengine 13, which operation generatesdrains which flow to the drainagetank 51, and the occurrence in the fuel tank 37 of an excessive vaporpressure which prevents discharge from the drainage tank 51 of thedrains flowing from the crankcase 17, whereby to cause accumulation ofsuch drains in the drainage tank 51 and consequent raising of the float59 so as to open the valve 81. Such opening permits fuel vapor flow tothe drainage tank upper portion 53 and through the duct 71 to the enginefuel feeding means 21 and, in particular, to the intake manifold 29.Because of continued engine operation, such fuel vapor as is dischargedinto the manifold 29 flows into the en'- gine cylinder and does not havean opportunity to enter the atmosphere. 1 I

In the disclosed construction, the conduits or ducts 73 and 79 have acommon portion 87. However, the conduits or duct 73 and 79 can beseparately connectedto the fuel tank upper portion 39.

The foregoing disclosed construction providesan arrangement wherebydrains may be returned to the fuel tank 37 and whereby vapor pressureswhich may be generated in the fuel tank 37 are prevented from escapingtothe atmosphere. Both functions'serve to prevent pollution and arehighly desirable. It is to be noted that excessive vapor pressure in thefuel tank 37 visvented only in response to engine operation and thatsuch venting occurs in such manner as to feed or supply the vented fuelvapors into the engine cylinder. In addition, the drains which arereturned to the fuel tank are sub.-

fuel economy, as well as pollution control. I

Various of the features of the invention are set forth in the followingclaims.

What is claimed is:

1. A fuel supply system for a two-stroke engine including a crankcaseand a fuel feeding means, said fuel supply system including a fuel tankconnected to said fuel feeding means, and means for preventing escape offuel vapor from said fuel tank when the engine is not operating and forventing of excessive vapor pressure in said fuel tank when the engine isoperating, said means for preventing escape of fuel vapor and forventing excess vapor pressure including a vented drainage tank, a drainsconduit communicating between said crankcase andsaid drainage tank,first conduit and valve means extending between said drainage tank andsaid fuel tank for providing controlled drainage flow and second conduitand valve means extending between said drainage tank and said fuel tankfor providing controlled vapor flow between said drainage tank and saidfuel tank.

2. A fuel supply system in accordance with claim l wherein said meansfor preventing escape of fuel vapor and for venting excess vaporpressure also functions to conduct drains from said crankcase to saidfuel tank.

3. A fuel supply system in accordance with claim I wherein said drainconduit includes a one-way valve affording flow from the crankcase tosaid drainage tank and preventing flow from from said drainage tank tothe crankcase.

4. A fuel supply system in accordance with claim l and further includinga vent line communicating between said drainage tank and the fuelfeeding means.

5. A fuel supply system in accordance with claim 1 wherein the fuelfeeding means includes a carburetor and a fuel inlet manifold connectingthe carburetor to the engine and further including a vent linecommunicating between the upper portion of said drainage tank and theintake manifold.

6. A fuel supply system in accordance with claim 1 wherein said firstconduit and valve means includes a drain line communicating between saiddrainage tank and said fuel tank and including a check valve affordingflow from said drainage tank to said fuel tank and preventing flow fromsaid fuel tank to said drainage tank, and wherein said second conduitand valve means includes a vent line between said fuel tank and theupper portion of said drainage tank and including a valve and a valveoperating member connected to said valve to move said valve to an openposition in response to engine operation.

7. A fuel supply system in accordance'with claim 6 wherein said valveoperating member comprises a float in said drainage tank operableuponthe accumulation of a predetermined amount of drains to causeopening of said valve.

8. A fuel supply system for a two-stroke engine including a crankcasehaving a' portion adapted for collecting drains and a fuel feedingmeans, said system comprising a fuel tank including a filler cap havingmeans for sealing the interior of said fuel tank from the atmosphere, afuel line connecting said fuel tank and the fuel feeding means, a venteddrainage tank, a conduit connecting said drainage tank to thedrains-collecting crankcase portion and including means preventing flowfrom said drainage tank to the crankcase, and

first valve and conduit means communicating between said drainage tankand said fuel tank for venting vapor pressure insaid fuel tank when apredetermined amount of drains accumulate in said drainage tank and thepressure generated by drains accumulation in said drainage tank is lessthan the vapor pressure in said fuel tank, and second conduit and valvemeans communicating between said drainage tank and said fuel tank fordischarging drains from said drainage tank to said fuel tank when thevapor pressure in said fuel tank is less than the pressure generated bydrains accumulation in said drainage tank.

9. A fuel supply system in accordance with claim 8 wherein said firstvalve and conduit means comprises a drain line communicating betweensaid drainage tank and said fuel tank and including a check valveaffording flow from said drainage tank to said fuel tank and preventingflow from said fuel tank to said drainage tank and wherein said secondvalve and conduit means comprises a vent line between said fuel tank andthe upper portion of said drainage tank and including a valve and avalve operating member connected to said valve to move said valve to anopen position only in response to engine operation and the presence ofexcessive vapor pressure in said fuel tank.

10. A fuel supply system in accordance with claim 9 wherein said valveoperating member comprises a float in said drainage tank operable uponthe accumulation of a predetermined amount of drains to cause opening ofsaid valve.

l l. A fuel supply system comprising a two-stroke engine including acrankcase having a portion adapted for collecting drains and an enginefuel feeding means including a carburetor and an air inlet manifoldconnecting said carburetor to said engine, a fuel tank including anupper portion, a lower portion, and a filler cap having means forsealing the interior of the fuel tank from the atmosphere, a fuel lineconnecting said fuel tank lower portion and said carburetor, a drainagetank including an upper portion, a lower portion, and a float mounted onsaid drainage tank for movement between a raised position and a loweredposition in accordance with the quantity of drains in said drainagetank, a conduit connecting said drainage tank to said crankcase portionand including means preventing flow from said drainage tank to saidcrankcase, a vent line connecting said drainage tank upper portion tosaid intake manifold, a drain line connecting said drainage tank lowerportion and fuel tank upper portion and including a check valveaffording flow from said drainage tank to said fuel tank and preventingflow from said fuel tank to said drainage tank, and a duct connectingsaid fuel tank upper portion and said drainage tank upper portion andincluding valve means connected to said float and operable when saidfloat is in said raised I position to open said valve and to close saidvalve when said float is lowered from said raised position toward saidlowered position.

12 A fuel supply system for a two-stroke engine including a crankcaseand a fuel feeding means, said fuel supply system including a fuel tankconnected to said fuel feeding means, and means for preventing escape offuel vapor from said fuel tankwhen the engine is not operating and forventing of excessive vapor pressure in said fuel tank when the engine isoperating, said means for preventing escape of fuel vapor and forventing excess vapor pressure including a vented drainage tank, a drainconduit communicating between said crankcase and said drainage tank,first conduit means extending between said drainage tank and said fueltank and including a one way valve affording flow from said drainagetank to said fuel tank and preventing flow from said fuel tank to saiddrainagetank, and second conduit means extending between said drainagetank and said fuel tank and including normally closed valve meansoperable to open in response to accumulation of drains in said drainagetank.

13. A fuel supply system including a crankcase and a fuel feeding means,said fuel supply system including a fuel tank connected to said fuelfeeding means, a vented drainage tank, a drain conduit between saidcrankcase and said drainage tank, a drain line communicating betweensaid drainage tank and said fuel tank operating member connected to saidvalve, and operable upon the accumulation of a predetermined amount ofdrains in said drainage tank to cause opening of said valve.

14. A fuel supply system in accordance with claim 13 wherein said valveoperating member comprises a float in said drainage tank.

##sia:

1. A fuel supply system for a two-stroke engine including a crankcaseand a fuel feeding means, said fuel supply system including a fuel tankconnected to said fuel feeding means, and means for preventing escape offuel vapor from said fuel tank when the engine is not operating and forventing of excessive vapor pressure in said fuel tank when the engine isoperating, said means for preventing escape of fuel vapor and forventing excess vapor pressure including a vented drainage tank, a drainsconduit communicating between said crankcase and said drainage tank,first conduit and valve means extending between said drainage tank andsaid fuel tank for providing controlled drainage flow and second conduitand valve means extending between said drainage tank and said fuel tankfor providing controlled vapor flow between said drainage tank and saidfuel tank.
 2. A fuel supply system in accordance with claim 1 whereinsaid means for preventing escape of fuel vapor and for venting excessvapor pressure also functions to conduct drains from said crankcase tosaid fuel tank.
 3. A fuel supply system in accordance with claim 1wherein said drain conduit includes a one-way valve affording flow fromthe crankcase to said drainage tank and preventing flow from from saiddrainage tank to the crankcase.
 4. A fuel supply system in accordancewith claim 1 and further including a vent line communicaTing betweensaid drainage tank and the fuel feeding means.
 5. A fuel supply systemin accordance with claim 1 wherein the fuel feeding means includes acarburetor and a fuel inlet manifold connecting the carburetor to theengine and further including a vent line communicating between the upperportion of said drainage tank and the intake manifold.
 6. A fuel supplysystem in accordance with claim 1 wherein said first conduit and valvemeans includes a drain line communicating between said drainage tank andsaid fuel tank and including a check valve affording flow from saiddrainage tank to said fuel tank and preventing flow from said fuel tankto said drainage tank, and wherein said second conduit and valve meansincludes a vent line between said fuel tank and the upper portion ofsaid drainage tank and including a valve and a valve operating memberconnected to said valve to move said valve to an open position inresponse to engine operation.
 7. A fuel supply system in accordance withclaim 6 wherein said valve operating member comprises a float in saiddrainage tank operable upon the accumulation of a predetermined amountof drains to cause opening of said valve.
 8. A fuel supply system for atwo-stroke engine including a crankcase having a portion adapted forcollecting drains and a fuel feeding means, said system comprising afuel tank including a filler cap having means for sealing the interiorof said fuel tank from the atmosphere, a fuel line connecting said fueltank and the fuel feeding means, a vented drainage tank, a conduitconnecting said drainage tank to the drains-collecting crankcase portionand including means preventing flow from said drainage tank to thecrankcase, and first valve and conduit means communicating between saiddrainage tank and said fuel tank for venting vapor pressure in said fueltank when a predetermined amount of drains accumulate in said drainagetank and the pressure generated by drains accumulation in said drainagetank is less than the vapor pressure in said fuel tank, and secondconduit and valve means communicating between said drainage tank andsaid fuel tank for discharging drains from said drainage tank to saidfuel tank when the vapor pressure in said fuel tank is less than thepressure generated by drains accumulation in said drainage tank.
 9. Afuel supply system in accordance with claim 8 wherein said first valveand conduit means comprises a drain line communicating between saiddrainage tank and said fuel tank and including a check valve affordingflow from said drainage tank to said fuel tank and preventing flow fromsaid fuel tank to said drainage tank and wherein said second valve andconduit means comprises a vent line between said fuel tank and the upperportion of said drainage tank and including a valve and a valveoperating member connected to said valve to move said valve to an openposition only in response to engine operation and the presence ofexcessive vapor pressure in said fuel tank.
 10. A fuel supply system inaccordance with claim 9 wherein said valve operating member comprises afloat in said drainage tank operable upon the accumulation of apredetermined amount of drains to cause opening of said valve.
 11. Afuel supply system comprising a two-stroke engine including a crankcasehaving a portion adapted for collecting drains and an engine fuelfeeding means including a carburetor and an air inlet manifoldconnecting said carburetor to said engine, a fuel tank including anupper portion, a lower portion, and a filler cap having means forsealing the interior of the fuel tank from the atmosphere, a fuel lineconnecting said fuel tank lower portion and said carburetor, a drainagetank including an upper portion, a lower portion, and a float mounted onsaid drainage tank for movement between a raised position and a loweredposition in accordance with the quantity of drains in said drainagetank, a conduit connecting said drainage tank to said crankcase portionand including means preventing flow from said drainage tank to saidcrankcase, a vent line connecting said drainage tank upper portion tosaid intake manifold, a drain line connecting said drainage tank lowerportion and fuel tank upper portion and including a check valveaffording flow from said drainage tank to said fuel tank and preventingflow from said fuel tank to said drainage tank, and a duct connectingsaid fuel tank upper portion and said drainage tank upper portion andincluding valve means connected to said float and operable when saidfloat is in said raised position to open said valve and to close saidvalve when said float is lowered from said raised position toward saidlowered position.
 12. A fuel supply system for a two-stroke engineincluding a crankcase and a fuel feeding means, said fuel supply systemincluding a fuel tank connected to said fuel feeding means, and meansfor preventing escape of fuel vapor from said fuel tank when the engineis not operating and for venting of excessive vapor pressure in saidfuel tank when the engine is operating, said means for preventing escapeof fuel vapor and for venting excess vapor pressure including a venteddrainage tank, a drain conduit communicating between said crankcase andsaid drainage tank, first conduit means extending between said drainagetank and said fuel tank and including a one way valve affording flowfrom said drainage tank to said fuel tank and preventing flow from saidfuel tank to said drainage tank, and second conduit means extendingbetween said drainage tank and said fuel tank and including normallyclosed valve means operable to open in response to accumulation ofdrains in said drainage tank.
 13. A fuel supply system including acrankcase and a fuel feeding means, said fuel supply system including afuel tank connected to said fuel feeding means, a vented drainage tank,a drain conduit between said crankcase and said drainage tank, a drainline communicating between said drainage tank and said fuel tank andincluding a check valve affording flow from said drainage tank to saidfuel tank and preventing flow from said fuel tank to said drainage tank,and a vent line between said fuel tank and the upper portion of saiddrainage tank and including a valve and a valve operating memberconnected to said valve, and operable upon the accumulation of apredetermined amount of drains in said drainage tank to cause opening ofsaid valve.
 14. A fuel supply system in accordance with claim 13 whereinsaid valve operating member comprises a float in said drainage tank.